1. Field of the Invention
The present invention generally relates to an improved valve. More specifically, the present invention is directed to a new, novel hemi-wedge valve employing a rotatable, curved wedge to enjoy advantages over conventional valves, e.g., the plug cock valve, the gate valve and the ball valve.
2. Description of the Background
Many valve types have been employed for stopping and controlling the flow of fluids in a pipe or other flow path. Each of these valves offers certain advantages while suffering from other disadvantages. These valve types include plug cock valves, ball valves, screw-down stop valves, angle valves, butterfly valves, gate valves and sluice valves.
A simple plug cock valve comprises a rotatable, tapered plug having a bore therethrough disposed in a complimentary tapered housing. The plug cock valve permits fluid flow to be fully stopped by rotating the plug not more than ninety degrees (90.degree. ). However, these valves offer only minimal graduated control of fluid flow by setting the plug cock at intermediate positions and require modification for use in high pressure environments.
Ball valves comprises a rotatable ball having a bore therethrough corresponding to the fluid flow path together with a seat for sealing with the ball surface. Ball valves operate similarly to the previously described plug cock valves and offer similar advantages and disadvantages.
More accurate flow control is obtained with conventional screw-down stop valves wherein a circular sealing element is disposed on the end of a threaded actuator or stem for cooperation with a seat disposed about an opening through which the fluid flows. Rotation of the actuator gradually lifts the sealing element, such as a washer or other device, away from the seat to provide more accurate control of gradual changes in the fluid flow. A variation of the screw-down stop valve is the needle valve where the stem
Conventional gate or sluice valves are often employed in high flow and high pressure operations. These valves comprise a solid gate which is moved perpendicularly into the fluid path to block the flow. These gates may have either flat or inclined sides forming a flat or wedge shaped gate which is moved generally perpendicular to the fluid flow by rotation of a threaded handle operatively connected thereto.
The valves described above fail to provide a valve operable between stops defining its fully opened and fully closed positions in a quarter of one rotation or less while providing improved sealing in high pressure applications and shielding of the seat surface from erosion by the flowing fluid in both the opened and closed positions. Those skilled in the art have long sought and will appreciate the novel features of the present invention which solves these problems.